import java.util.Scanner;

/**
 * Created with IntelliJ IDEA.
 * Description:
 * User:26554
 * Date:2024-11-03
 * Time:23:26
 */
public class Text {
    public static void main(String[] args) {
        Scanner x = new Scanner(System.in);
        int y = x.nextInt();
        int sum = 1;
        for (int i = 1; i <= y; i++) {
            sum=sum*i;
        }
        System.out.println(sum);
    }
}
